[Analgesic effects of topical opioids: are they effective?]

Recent research has revealed the presence of opioid receptors in inflamed peripheral tissues. This gives rise to the possibility of treating the pain caused by wounds with the advantage of reducing the secondary effects related to the use of opioids and at the same time rendering their use more efficacious. The theory of a peripheral analgesic action of opioids has been tested in a variety of situations, in particular in brachial plexus blocks and intra-articular injections. In addition, the analgesic effect of opioids has been tested by cutaneous application for various conditions but on only a limited number of patients. On the basis of these case reports, we cannot conclude that the peripheral use of opioids is efficacious and the topical use of opioids cannot be recommended unless done within the framework of a controlled clinical trial.